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Xi D. Case report: Francisella philomiragia bacteremia in a patient with acute lymphoblastic leukemia. Front Cell Infect Microbiol 2023; 13:1206972. [PMID: 37780860 PMCID: PMC10538626 DOI: 10.3389/fcimb.2023.1206972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Accepted: 08/18/2023] [Indexed: 10/03/2023] Open
Abstract
Francisella philomiragia is a Gram-negative coccobacillus, which is a very rare human opportunistic pathogen causing pneumonia and systemic infection. It is difficult to identify this bacterium through conventional Gram-staining and biochemical methods due to an amorphous Gram stain appearance after 24 h culture and its relatively fastidious and slow growth giving weak and/or delayed reactions in biochemical tests. It is often misidentified as other bacteria including Haemophilus spp., Pseudomonas aeruginosa, or Sphingomonas paucimobilis. False identification may delay the therapy of the patients and even endanger the patient's life. Here, we report a case of a 34-year-old man with acute lymphoblastic leukemia infected by F. philomiragia, which was almost misdiagnosed. This case describes our identification of a patient with a systemic F. philomiragia infection. To our knowledge, this is the first such case reported in China.
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Affiliation(s)
- Dee Xi
- Department of Clinical Laboratory, The First College of Clinical Medical Science, China Three Gorges University, Yichang Central People’s Hospital, Yichang, China
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Bouras H, Quesnelle Y, Barozet A, Goux D, Blin JL, Savary M, Zatylny-Gaudin C, Houssin M. First isolation of Francisella halioticida strains from blue mussel (Mytilus edulis) in Normandy, France. J Invertebr Pathol 2023; 200:107950. [PMID: 37301277 DOI: 10.1016/j.jip.2023.107950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 04/26/2023] [Accepted: 06/02/2023] [Indexed: 06/12/2023]
Abstract
Mass mortality events affecting the blue mussels Mytilus edulis have been observed in France since 2014. The DNA of the bacterium Francisella halioticida, reported as pathogen of giant abalone (Haliotis gigantea) and Yesso scallop (Mizuhopecten yessoensis) has been detected recently in mussels from areas suffering mortalities. Isolation of this bacterium was attempted from individuals collected during mortality events. Identification was performed by 16S rRNA gene sequencing, real-time specific PCR and MALDI-ToF using spectra produced from the strain 8472-13A isolated from diseased Yesso scallop in Canada. Five isolates were identified as F. halioticida by real-time specific PCR and 16S rRNA sequencing. MALDI-ToF allowed the direct identification of four isolates (FR22a,b,c,d) which had 100% identity on the 16S rRNA gene with the known strains. On the other hand, one isolate (FR21) was not recognized by MALDI-ToF and had 99.9% identity on the 16S rRNA gene. The FR22 isolates showed difficult growth and required media optimization, which was not the case with the FR21 isolate. For these reasons, it was hypothesized that two type strains are present on French coasts, named FR21 and FR22. The FR21 isolate was selected for phenotypic analysis (growth curve, biochemical characteristics, electron microscopy), phylogenetic analysis and an experimental challenge. This isolate showed distinct differences compared to published F. halioticida strains, both at phenotypic and genotypic levels. Experimental infections of adult mussels led to 36% mortalities in 23 days following intramuscular injection with 3 × 107 CFU while a lower dose (3 × 103 CFU) did not lead to significant mortalities. In the context of this study, the strain FR21 was not virulent towards adult mussels.
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Affiliation(s)
- Hélène Bouras
- Université de Caen-Normandie, Sorbonne Université, MNHN, UA, CNRS, IRD, Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Esplanade de la Paix, 14032 Caen, France; LABÉO, Research department; 1 Route de Rosel, 14053 Caen Cedex 4, France.
| | - Yann Quesnelle
- LABÉO, Research department; 1 Route de Rosel, 14053 Caen Cedex 4, France
| | - Alix Barozet
- LABÉO, Research department; 1 Route de Rosel, 14053 Caen Cedex 4, France
| | - Didier Goux
- Normandie Université, UNICAEN, CMAbio3 (Centre de Microscopie Appliquée à la Biologie), SF EMerode, Esplanade de la Paix, 14032 Caen, France; Normandie Université, ENSICAEN, UNICAEN, CNRS, UMR 6508 CRISMAT, 6 boulevard du Maréchal Juin, 14000 Caen, France
| | - Jean-Louis Blin
- Synergie Mer et Littoral (SMEL), Zone Conchylicole, Blainville-sur-mer, France
| | - Manuel Savary
- Comité Régional de Conchyliculture (CRC) Normandie-Mer du Nord, 35 rue du littoral, 50560 Gouville-sur-Mer, France
| | - Céline Zatylny-Gaudin
- Université de Caen-Normandie, Sorbonne Université, MNHN, UA, CNRS, IRD, Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Esplanade de la Paix, 14032 Caen, France
| | - Maryline Houssin
- Université de Caen-Normandie, Sorbonne Université, MNHN, UA, CNRS, IRD, Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Esplanade de la Paix, 14032 Caen, France; LABÉO, Research department; 1 Route de Rosel, 14053 Caen Cedex 4, France
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3
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Kijewska A, Koroza A, Grudlewska-Buda K, Kijewski T, Wiktorczyk-Kapischke N, Zorena K, Skowron K. Molluscs-A ticking microbial bomb. Front Microbiol 2023; 13:1061223. [PMID: 36699600 PMCID: PMC9868776 DOI: 10.3389/fmicb.2022.1061223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 12/20/2022] [Indexed: 01/11/2023] Open
Abstract
Bivalve shellfish consumption (ark shells, clams, cockles, and oysters) has increased over the last decades. Following this trend, infectious disease outbreaks associated with their consumption have been reported more frequently. Molluscs are a diverse group of organisms found wild and farmed. They are common on our tables, but unfortunately, despite their great taste, they can also pose a threat as a potential vector for numerous species of pathogenic microorganisms. Clams, in particular, might be filled with pathogens because of their filter-feeding diet. This specific way of feeding favors the accumulation of excessive amounts of pathogenic microorganisms like Vibrio spp., including Vibrio cholerae and V. parahaemolyticus, Pseudomonas aeruginosa, Escherichia coli, Arcobacter spp., and fecal coliforms, and intestinal enterococci. The problems of pathogen dissemination and disease outbreaks caused by exogenous bacteria in many geographical regions quickly became an unwanted effect of globalized food supply chains, global climate change, and natural pathogen transmission dynamics. Moreover, some pathogens like Shewanella spp., with high zoonotic potential, are spreading worldwide along with food transport. These bacteria, contained in food, are also responsible for the potential transmission of antibiotic-resistance genes to species belonging to the human microbiota. Finally, they end up in wastewater, thus colonizing new areas, which enables them to introduce new antibiotic-resistance genes (ARG) into the environment and extend the existing spectrum of ARGs already present in local biomes. Foodborne pathogens require modern methods of detection. Similarly, detecting ARGs is necessary to prevent resistance dissemination in new environments, thus preventing future outbreaks, which could threaten associated consumers and workers in the food processing industry.
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Affiliation(s)
- Agnieszka Kijewska
- Department of Immunobiology and Environmental Microbiology, Institute of Maritime and Tropical Medicine, Medical University of Gdańsk, Gdańsk, Poland
| | - Aleksandra Koroza
- Department of Climate and Ocean Research and Education Laboratory, Institute of Oceanology Polish Academy of Science, Sopot, Poland
| | - Katarzyna Grudlewska-Buda
- Department of Microbiology, Nicolaus Copernicus University in Toruń, Ludwik Rydygier Collegium Medicum, Bydgoszcz, Poland
| | - Tomasz Kijewski
- Department of Climate and Ocean Research and Education Laboratory, Institute of Oceanology Polish Academy of Science, Sopot, Poland
| | - Natalia Wiktorczyk-Kapischke
- Department of Microbiology, Nicolaus Copernicus University in Toruń, Ludwik Rydygier Collegium Medicum, Bydgoszcz, Poland
| | - Katarzyna Zorena
- Department of Immunobiology and Environmental Microbiology, Institute of Maritime and Tropical Medicine, Medical University of Gdańsk, Gdańsk, Poland
| | - Krzysztof Skowron
- Department of Microbiology, Nicolaus Copernicus University in Toruń, Ludwik Rydygier Collegium Medicum, Bydgoszcz, Poland,*Correspondence: Krzysztof Skowron,
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Wagner DM, Birdsell DN, McDonough RF, Nottingham R, Kocos K, Celona K, Özsürekci Y, Öhrman C, Karlsson L, Myrtennäs K, Sjödin A, Johansson A, Keim PS, Forsman M, Sahl JW. Genomic characterization of Francisella tularensis and other diverse Francisella species from complex samples. PLoS One 2022; 17:e0273273. [PMID: 36223396 PMCID: PMC9555625 DOI: 10.1371/journal.pone.0273273] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 09/19/2022] [Indexed: 11/06/2022] Open
Abstract
Francisella tularensis, the bacterium that causes the zoonosis tularemia, and its genetic near neighbor species, can be difficult or impossible to cultivate from complex samples. Thus, there is a lack of genomic information for these species that has, among other things, limited the development of robust detection assays for F. tularensis that are both specific and sensitive. The objective of this study was to develop and validate approaches to capture, enrich, sequence, and analyze Francisella DNA present in DNA extracts generated from complex samples. RNA capture probes were designed based upon the known pan genome of F. tularensis and other diverse species in the family Francisellaceae. Probes that targeted genomic regions also present in non-Francisellaceae species were excluded, and probes specific to particular Francisella species or phylogenetic clades were identified. The capture-enrichment system was then applied to diverse, complex DNA extracts containing low-level Francisella DNA, including human clinical tularemia samples, environmental samples (i.e., animal tissue and air filters), and whole ticks/tick cell lines, which was followed by sequencing of the enriched samples. Analysis of the resulting data facilitated rigorous and unambiguous confirmation of the detection of F. tularensis or other Francisella species in complex samples, identification of mixtures of different Francisella species in the same sample, analysis of gene content (e.g., known virulence and antimicrobial resistance loci), and high-resolution whole genome-based genotyping. The benefits of this capture-enrichment system include: even very low target DNA can be amplified; it is culture-independent, reducing exposure for research and/or clinical personnel and allowing genomic information to be obtained from samples that do not yield isolates; and the resulting comprehensive data not only provide robust means to confirm the presence of a target species in a sample, but also can provide data useful for source attribution, which is important from a genomic epidemiology perspective.
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Affiliation(s)
- David M. Wagner
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
- * E-mail:
| | - Dawn N. Birdsell
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Ryelan F. McDonough
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Roxanne Nottingham
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Karisma Kocos
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Kimberly Celona
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Yasemin Özsürekci
- Department of Pediatric Infectious Diseases, Hacettepe University Faculty of Medicine, Ankara, Turkey
| | - Caroline Öhrman
- CBRN Defence and Security, Swedish Defence Research Agency, Umeå, Sweden
| | - Linda Karlsson
- CBRN Defence and Security, Swedish Defence Research Agency, Umeå, Sweden
| | - Kerstin Myrtennäs
- CBRN Defence and Security, Swedish Defence Research Agency, Umeå, Sweden
| | - Andreas Sjödin
- CBRN Defence and Security, Swedish Defence Research Agency, Umeå, Sweden
| | - Anders Johansson
- Department of Clinical Microbiology, Umeå University, Umeå, Sweden
| | - Paul S. Keim
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Mats Forsman
- CBRN Defence and Security, Swedish Defence Research Agency, Umeå, Sweden
| | - Jason W. Sahl
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
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Carvajal-Agudelo JD, Ramírez-Chaves HE, Ossa-López PA, Rivera-Páez FA. Bacteria related to tick-borne pathogen assemblages in Ornithodoros cf. hasei (Acari: Argasidae) and blood of the wild mammal hosts in the Orinoquia region, Colombia. EXPERIMENTAL & APPLIED ACAROLOGY 2022; 87:253-271. [PMID: 35829939 PMCID: PMC9424158 DOI: 10.1007/s10493-022-00724-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 06/16/2022] [Indexed: 05/19/2023]
Abstract
Interest in research on soft ticks has increased in recent decades, leading to valuable insight into their role as disease vectors. The use of metagenomics-based analyses have helped to elucidate ecological factors involved in pathogen, vector, and host dynamics. To understand the main bacterial assemblages present in Ornithodoros cf. hasei and its mammalian hosts, 84 ticks and 13 blood samples from bat hosts (Chiroptera) were selected, and the 16S rRNA gene V4 region was sequenced in five pools (each one related to each host-tick pairing). Bacterial taxonomic assignment analyses were performed by comparing operational taxonomic units (OTUs) shared between ticks and their host blood. This analysis showed the presence of Proteobacteria (38.8%), Enterobacteriaceae (25%), Firmicutes (12.3%), and Actinobacteria (10.9%) within blood samples, and Rickettsiaceae (39%), Firmicutes (25%), Actinobacteria (13.1%), and Proteobacteria (9%) within ticks. Species related to potentially pathogenic genera were detected in ticks, such as Borrelia sp., Bartonella tamiae, Ehrlichia sp. and Rickettsia-like endosymbiont, and the presence of these organisms was found in all analyzed bat species (Cynomops planirostris, Molossus pretiosus, Noctilio albiventris), and O. cf. hasei. About 41-48.6% of bacterial OTUs (genera and species) were shared between ticks and the blood of bat hosts. Targeted metagenomic screening techniques allowed the detection of tick-associated pathogens for O. cf. hasei and small mammals for the first time, enabling future research on many of these pathogens.
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Affiliation(s)
- Juan D Carvajal-Agudelo
- Grupo de Investigación en Genética, Biodiversidad y Manejo de Ecosistemas (GEBIOME), Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad de Caldas, Calle 65 N° 26-10, 170004, Manizales, Caldas, Colombia
| | - Héctor E Ramírez-Chaves
- Grupo de Investigación en Genética, Biodiversidad y Manejo de Ecosistemas (GEBIOME), Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad de Caldas, Calle 65 N° 26-10, 170004, Manizales, Caldas, Colombia
- Centro de Museos, Museo de Historia Natural, Universidad de Caldas, Calle 65 N° 26-10, 170004, Manizales, Caldas, Colombia
| | - Paula A Ossa-López
- Grupo de Investigación en Genética, Biodiversidad y Manejo de Ecosistemas (GEBIOME), Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad de Caldas, Calle 65 N° 26-10, 170004, Manizales, Caldas, Colombia
- Doctorado en Ciencias, Biología, Facultad de Ciencias Exactas y Naturales, Universidad de Caldas, Calle 65 No. 26-10, 170004, Manizales, Caldas, Colombia
| | - Fredy A Rivera-Páez
- Grupo de Investigación en Genética, Biodiversidad y Manejo de Ecosistemas (GEBIOME), Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad de Caldas, Calle 65 N° 26-10, 170004, Manizales, Caldas, Colombia.
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Seong HJ, Kim JJ, Kim T, Ahn SJ, Rho M, Sul WJ. A case study on the distribution of the environmental resistome in Korean shrimp farms. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 227:112858. [PMID: 34653940 DOI: 10.1016/j.ecoenv.2021.112858] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 09/13/2021] [Accepted: 09/14/2021] [Indexed: 06/13/2023]
Abstract
Hundreds of tons of antibiotics are widely used in aquaculture to prevent microbial infections and promote fish growth. However, the overuse of antibiotics and chemical products can lead to the selection and spreading of antibiotic-resistant bacteria (ARB) and antimicrobial resistance genes (ARGs), which are of great concern considering the threat to public health worldwide. Here, in-depth metagenome sequencing was performed to explore the environmental resistome and ARB distribution across farming stages in shrimp farms and examine anthropogenic effects in nearby coastal waters. A genome-centric analysis using a metagenome binning approach allowed us to accurately investigate the distribution of pathogens and ARG hosts in shrimp farms. The diversity of resistomes was higher in shrimp farms than in coastal waters, and the distribution of resistomes was dependent on the farming stage. In particular, the tetracycline resistance gene was found mainly at the early post-larval stage regardless of the farm. The metagenome-assembled genomes of Vibrio spp. were dominant at this stage and harbored tet34, which is known to confer resistance to oxytetracycline. In addition, opportunistic pathogens such as Francisella, Mycoplasma, Photobacterium, and Vibrio were found in abundance in shrimp farms, which had multiple virulence factors. This study highlights the increased resistance diversity and environmental selection of pathogens in shrimp farms. The use of environmental pollutants on farms may cause an increase in resistome diversity/abundance and the transmission of pathogens to the surrounding environment, which may pose future risks to public health and aquatic organisms.
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Affiliation(s)
- Hoon Je Seong
- Department of Systems Biotechnology, Chung-Ang University, Anseong 17546, Republic of Korea
| | - Jin Ju Kim
- Department of Systems Biotechnology, Chung-Ang University, Anseong 17546, Republic of Korea
| | - Taeyune Kim
- Department of Systems Biotechnology, Chung-Ang University, Anseong 17546, Republic of Korea
| | - Sung Jae Ahn
- Department of Systems Biotechnology, Chung-Ang University, Anseong 17546, Republic of Korea
| | - Mina Rho
- Department of Computer Science, Hanyang University, Seoul 04763, Republic of Korea
| | - Woo Jun Sul
- Department of Systems Biotechnology, Chung-Ang University, Anseong 17546, Republic of Korea.
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Brunet CD, Hennebique A, Peyroux J, Pelloux I, Caspar Y, Maurin M. Presence of Francisella tularensis subsp. holarctica DNA in the Aquatic Environment in France. Microorganisms 2021; 9:microorganisms9071398. [PMID: 34203503 PMCID: PMC8306966 DOI: 10.3390/microorganisms9071398] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 06/24/2021] [Accepted: 06/25/2021] [Indexed: 01/08/2023] Open
Abstract
In 2018, the incidence of tularemia increased twofold in the west of France, with many pneumonic forms, suggesting environmental sources of infection. We investigated the presence of Francisellatularensis subsp. holarctica and other Francisella species DNA in the natural aquatic environment of this geographic area. Two sampling campaigns, in July 2019 and January 2020, allowed the collection of 87 water samples. Using a combination of real-time PCR assays, we tested the presence of either Francisella sp., F. tularensis/F. novicida, and F. tularensis subsp. holarctica, the latter being the only tularemia agent in Europe. Among 57 water samples of the first campaign, 15 (26.3%) were positive for Francisella sp., nine (15.8%) for F. tularensis and/or F. novicida, and four (7.0%) for F. tularensis subsp. holarctica. Ratios were 25/30 (83.3%), 24/30 (80.0%), and 4/30 (13.3%) for the second campaign. Among the thirty sites sampled during the two campaigns, nine were positive both times for Francisella sp., seven for F. tularensis and/or F. novicida, and one for F. tularensis subsp. holarctica. Altogether, our study reveals a high prevalence of Francisella sp. DNA (including the tularemia agent) in the studied aquatic environment. This aquatic environment could therefore participate in the endemicity of tularemia in the west of France.
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Affiliation(s)
- Camille D. Brunet
- Centre National de la Recherche Scientifique, Université Grenoble Alpes, TIMC, UMR5525, 38000 Grenoble, France; (C.D.B.); (A.H.); (J.P.); (Y.C.)
| | - Aurélie Hennebique
- Centre National de la Recherche Scientifique, Université Grenoble Alpes, TIMC, UMR5525, 38000 Grenoble, France; (C.D.B.); (A.H.); (J.P.); (Y.C.)
- Centre National de Référence des Francisella, Centre Hospitalier Universitaire Grenoble Alpes, 38000 Grenoble, France;
| | - Julien Peyroux
- Centre National de la Recherche Scientifique, Université Grenoble Alpes, TIMC, UMR5525, 38000 Grenoble, France; (C.D.B.); (A.H.); (J.P.); (Y.C.)
| | - Isabelle Pelloux
- Centre National de Référence des Francisella, Centre Hospitalier Universitaire Grenoble Alpes, 38000 Grenoble, France;
| | - Yvan Caspar
- Centre National de la Recherche Scientifique, Université Grenoble Alpes, TIMC, UMR5525, 38000 Grenoble, France; (C.D.B.); (A.H.); (J.P.); (Y.C.)
- Centre National de Référence des Francisella, Centre Hospitalier Universitaire Grenoble Alpes, 38000 Grenoble, France;
| | - Max Maurin
- Centre National de la Recherche Scientifique, Université Grenoble Alpes, TIMC, UMR5525, 38000 Grenoble, France; (C.D.B.); (A.H.); (J.P.); (Y.C.)
- Centre National de Référence des Francisella, Centre Hospitalier Universitaire Grenoble Alpes, 38000 Grenoble, France;
- Correspondence:
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Hennebique A, Boisset S, Maurin M. Tularemia as a waterborne disease: a review. Emerg Microbes Infect 2019; 8:1027-1042. [PMID: 31287787 PMCID: PMC6691783 DOI: 10.1080/22221751.2019.1638734] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 06/27/2019] [Indexed: 12/20/2022]
Abstract
Francisella tularensis is a Gram-negative, intracellular bacterium causing the zoonosis tularemia. This highly infectious microorganism is considered a potential biological threat agent. Humans are usually infected through direct contact with the animal reservoir and tick bites. However, tularemia cases also occur after contact with a contaminated hydro-telluric environment. Water-borne tularemia outbreaks and sporadic cases have occurred worldwide in the last decades, with specific clinical and epidemiological traits. These infections represent a major public health and military challenge. Human contaminations have occurred through consumption or use of F. tularensis-contaminated water, and various aquatic activities such as swimming, canyoning and fishing. In addition, in Sweden and Finland, mosquitoes are primary vectors of tularemia due to infection of mosquito larvae in contaminated aquatic environments. The mechanisms of F. tularensis survival in water may include the formation of biofilms, interactions with free-living amoebae, and the transition to a 'viable but nonculturable' state, but the relative contribution of these possible mechanisms remains unknown. Many new aquatic species of Francisella have been characterized in recent years. F. tularensis likely shares with these species an ability of long-term survival in the aquatic environment, which has to be considered in terms of tularemia surveillance and control.
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Affiliation(s)
- Aurélie Hennebique
- Centre National de Référence des Francisella, Institut de Biologie et de Pathologie, Centre Hospitalier Universitaire Grenoble Alpes, Grenoble, France
- Université Grenoble Alpes, Centre National de la Recherche Scientifique, TIMC-IMAG, Grenoble, France
| | - Sandrine Boisset
- Centre National de Référence des Francisella, Institut de Biologie et de Pathologie, Centre Hospitalier Universitaire Grenoble Alpes, Grenoble, France
- Université Grenoble Alpes, Centre National de la Recherche Scientifique, TIMC-IMAG, Grenoble, France
| | - Max Maurin
- Centre National de Référence des Francisella, Institut de Biologie et de Pathologie, Centre Hospitalier Universitaire Grenoble Alpes, Grenoble, France
- Université Grenoble Alpes, Centre National de la Recherche Scientifique, TIMC-IMAG, Grenoble, France
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9
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Janse I, van der Plaats RQJ, de Roda Husman AM, van Passel MWJ. Environmental Surveillance of Zoonotic Francisella tularensis in the Netherlands. Front Cell Infect Microbiol 2018; 8:140. [PMID: 29868496 PMCID: PMC5951967 DOI: 10.3389/fcimb.2018.00140] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 04/18/2018] [Indexed: 12/25/2022] Open
Abstract
Tularemia is an emerging zoonosis caused by the Gram-negative bacterium Francisella tularensis, which is able to infect a range of animal species and humans. Human infections occur through contact with animals, ingestion of food, insect bites or exposure to aerosols or water, and may lead to serious disease. F. tularensis may persist in aquatic reservoirs. In the Netherland, no human tularemia cases were notified for over 60 years until in 2011 an endemic patient was diagnosed, followed by 17 cases in the 6 years since. The re-emergence of tularemia could be caused by changes in reservoirs or transmission routes. We performed environmental surveillance of F. tularensis in surface waters in the Netherlands by using two approaches. Firstly, 339 samples were obtained from routine monitoring -not related to tularemia- at 127 locations that were visited between 1 and 8 times in 2015 and 2016. Secondly, sampling efforts were performed after reported tularemia cases (n = 8) among hares or humans in the period 2013–2017. F. tularensis DNA was detected at 17% of randomly selected surface water locations from different parts of the country. At most of these positive locations, DNA was not detected at each time point and levels were very low, but at two locations contamination was clearly higher. From 7 out of the 8 investigated tularemia cases, F. tularensis DNA was detected in at least one surface water sample collected after the case. By using a protocol tailored for amplification of low amounts of environmental DNA, 10 gene targets were sequenced. Presence of F. tularensis subspecies holarctica was confirmed in 4 samples, and in 2 of these, clades B.12 and B.6 were identified. This study shows that for tularemia, information regarding the spatial and temporal distribution of its causative agent could be derived from environmental surveillance of surface waters. Tracking a particular strain in the environment as source of infection is feasible and could be substantiated by genotyping, which was achieved in water samples with only low levels of F. tularemia present. These techniques allow the establishment of a link between tularemia cases and environmental samples without the need for cultivation.
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Affiliation(s)
- Ingmar Janse
- Zoonoses and Environmental Microbiology, Centre for Infectious Diseases Control, National Institute for Public Health and the Environment, Bilthoven, Netherlands
| | - Rozemarijn Q J van der Plaats
- Zoonoses and Environmental Microbiology, Centre for Infectious Diseases Control, National Institute for Public Health and the Environment, Bilthoven, Netherlands
| | - Ana Maria de Roda Husman
- Zoonoses and Environmental Microbiology, Centre for Infectious Diseases Control, National Institute for Public Health and the Environment, Bilthoven, Netherlands
| | - Mark W J van Passel
- Zoonoses and Environmental Microbiology, Centre for Infectious Diseases Control, National Institute for Public Health and the Environment, Bilthoven, Netherlands
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10
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Gignoux-Wolfsohn SA, Aronson FM, Vollmer SV. Complex interactions between potentially pathogenic, opportunistic, and resident bacteria emerge during infection on a reef-building coral. FEMS Microbiol Ecol 2017. [PMID: 28637338 DOI: 10.1093/femsec/fix080] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Increased bacterial diversity on diseased corals can obscure disease etiology and complicate our understanding of pathogenesis. To untangle microbes that may cause white band disease signs from microbes responding to disease, we inoculated healthy Acropora cervicornis corals with an infectious dose from visibly diseased corals. We sampled these dosed corals and healthy controls over time for sequencing of the bacterial 16S region. Endozoicomonas were associated with healthy fragments from 4/10 colonies, dominating microbiomes before dosing and decreasing over time only in corals that displayed disease signs, suggesting a role in disease resistance. We grouped disease-associated bacteria by when they increased in abundance (primary vs secondary) and whether they originated in the dose (colonizers) or the previously healthy corals (responders). We found that all primary responders increased in all dosed corals regardless of final disease state and are therefore unlikely to cause disease signs. In contrast, primary colonizers in the families Pasteurellaceae and Francisellaceae increased solely in dosed corals that ultimately displayed disease signs, and may be infectious foreign bacteria involved in the development of disease signs. Moving away from a static comparison of diseased and healthy bacterial communities, we provide a framework to identify key players in other coral diseases.
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Affiliation(s)
- Sarah A Gignoux-Wolfsohn
- Department of Ecology, Evolution, & Natural Resources School of Environmental and Biological Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901-8525, USA
| | - Felicia M Aronson
- Marine Science Center, Northeastern University, Nahant, MA 01908, USA
| | - Steven V Vollmer
- Marine Science Center, Northeastern University, Nahant, MA 01908, USA
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11
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Brenz Y, Winther-Larsen HC, Hagedorn M. Expanding Francisella models: Pairing up the soil amoeba Dictyostelium with aquatic Francisella. Int J Med Microbiol 2017; 308:32-40. [PMID: 28843671 DOI: 10.1016/j.ijmm.2017.08.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 07/31/2017] [Accepted: 08/04/2017] [Indexed: 12/19/2022] Open
Abstract
The bacterial genus Francisella comprises highly pathogenic species that infect mammals, arthropods, fish and protists. Understanding virulence and host defense mechanisms of Francisella infection relies on multiple animal and cellular model systems. In this review, we want to summarize the most commonly used Francisella host model platforms and highlight novel, alternative model systems using aquatic Francisella species. Established mouse and macrophage models contributed extensively to our understanding of Francisella infection. However, murine and human cells display significant differences in their response to Francisella infection. The zebrafish and the amoeba Dictyostelium are well-established model systems for host-pathogen interactions and open up opportunities to investigate bacterial virulence and host defense. Comparisons between model systems using human and fish pathogenic Francisella species revealed shared virulence strategies and pathology between them. Hence, zebrafish and Dictyostelium might complement current model systems to find new vaccine candidates and contribute to our understanding of Francisella infection.
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Affiliation(s)
- Yannick Brenz
- Department of Parasitology, Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht-Straße 74, 20359 Hamburg, Germany.
| | - Hanne C Winther-Larsen
- Centre for Integrative Microbial Evolution (CIME) and Department of Pharmaceutical Biosciences, University of Oslo, Sem Sælands vei 3, 0371 Oslo, Norway.
| | - Monica Hagedorn
- Department of Life Sciences and Chemistry, Jacobs University, Campus Ring 1, 28759 Bremen, Germany.
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12
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Assis GBN, de Oliveira TF, Gardner IA, Figueiredo HCP, Leal CAG. Sensitivity and specificity of real-time PCR and bacteriological culture for francisellosis in farm-raised Nile tilapia (Oreochromis niloticus L.). JOURNAL OF FISH DISEASES 2017; 40:785-795. [PMID: 27670740 DOI: 10.1111/jfd.12559] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 08/09/2016] [Accepted: 08/11/2016] [Indexed: 06/06/2023]
Abstract
Despite the worldwide occurrence of Francisella noatunensis subsp. orientalis (Fno) infection in farmed tilapia, sensitivity and specificity estimates of commonly used diagnostic tests have not been reported. This study aimed to estimate the sensitivity and specificity of bacteriological culture and qPCR to detect Fno infection. We tested 559 fish, sampled from four farms with different epidemiological scenarios: (i) healthy fish in a hatchery free of Fno; (ii) targeted sampling of diseased fish with suggestive external clinical signs of francisellosis during an outbreak; (iii) convenience sampling of diseased and clinically healthy fish during an outbreak; and (iv) sampling of healthy fish in a cage farm without a history of outbreaks, but with francisellosis reported in other farms in the same reservoir. The qPCR had higher median sensitivity (range, 48.8-99.5%) than culture (range, 1.6-74.4%). Culture had a substantially lower median sensitivity (1.6%) than qPCR (48.8%) to detect Fno in carrier tilapia (farm 4). Median specificity estimates for both tests were >99.2%. The qPCR is the superior test for use in surveillance and monitoring programmes for francisellosis in farmed Nile tilapia, but both tests have high sensitivity and specificity which make them fit for use in the diagnosis of Fno outbreaks.
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Affiliation(s)
- G B N Assis
- AQUAVET, Laboratory of Aquatic Animal Diseases, Veterinary School, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - T F de Oliveira
- AQUAVET, Laboratory of Aquatic Animal Diseases, Veterinary School, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - I A Gardner
- Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE, Canada
| | - H C P Figueiredo
- AQUAVET, Laboratory of Aquatic Animal Diseases, Veterinary School, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
- AQUACEN - National Reference Laboratory of Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Veterinary School, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - C A G Leal
- AQUAVET, Laboratory of Aquatic Animal Diseases, Veterinary School, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
- AQUACEN - National Reference Laboratory of Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Veterinary School, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
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13
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Lampe EO, Tandberg JI, Rishovd AL, Winther-Larsen HC. Francisella noatunensis ssp. noatunensis iglC deletion mutant protects adult zebrafish challenged with acute mortality dose of wild-type strain. DISEASES OF AQUATIC ORGANISMS 2017; 123:123-140. [PMID: 28262634 DOI: 10.3354/dao03087] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The intracellular fish pathogen Francisella noatunensis remains an unsolved problem for aquaculture worldwide and an efficient vaccine is needed. In Francisella sp., IglC is an important virulence factor necessary for intracellular growth and escape from phagolysosomes. Deletion of the intracellular growth locus C (iglC) in Francisella sp. causes attenuation, but vaccine potential has only been attributed to ΔiglC from Francisella noatunensis ssp. orientalis, a warm-water fish pathogen. A ΔiglC mutant was constructed in the cold-water fish pathogen F. noatunensis ssp. noatunensis (Fnn), which causes francisellosis in Atlantic cod; the mutant was assessed in primary head kidney leucocytes from Atlantic cod. Fluorescence microscopy revealed reduced growth, while qPCR revealed an initial increase followed by a reduction in mutant genomes. Mutant-infected cod leucocytes presented higher interleukin 1 beta (il1β) and interleukin 8 (il8) transcription than wild-type (WT)-infected cells. Two doses of mutant and WT were tested in an adult zebrafish model whereupon 3 × 109 CFU caused acute disease and 3 × 107 CFU caused low mortality regardless of strain. However, splenomegaly developed only in the WT-infected zebrafish. Immunization with 7 × 106 CFU of Fnn ΔiglC protected zebrafish against challenge with a lethal dose of Fnn WT, and bacterial load was minimized within 28 d. Immunized fish had lower interleukin 6 (il6) and il8 transcription in kidney and prolonged interferon-gamma (ifng) transcription in spleens after challenge compared with non-immunized fish. Our data suggest an immunogenic potential of Fnn ΔiglC and indicate important cytokines associated with francisellosis pathogenesis and protection.
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Affiliation(s)
- Elisabeth O Lampe
- Center for Integrative Microbiology and Evolution, Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, 0316 Oslo, Norway
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14
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Kreitmann L, Terriou L, Launay D, Caspar Y, Courcol R, Maurin M, Lemaître N. Disseminated Infection Caused by Francisella philomiragia, France, 2014. Emerg Infect Dis 2016; 21:2260-1. [PMID: 26583375 PMCID: PMC4672438 DOI: 10.3201/eid2112.150615] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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15
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Pucciarelli S, Devaraj RR, Mancini A, Ballarini P, Castelli M, Schrallhammer M, Petroni G, Miceli C. Microbial Consortium Associated with the Antarctic Marine Ciliate Euplotes focardii: An Investigation from Genomic Sequences. MICROBIAL ECOLOGY 2015; 70:484-97. [PMID: 25704316 PMCID: PMC4494151 DOI: 10.1007/s00248-015-0568-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 01/08/2015] [Indexed: 05/23/2023]
Abstract
We report the characterization of the bacterial consortium associated to Euplotes focardii, a strictly psychrophilic marine ciliate that was maintained in laboratory cultures at 4 °C after its first isolation from Terra Nova Bay, in Antarctica. By Illumina genome analyser, we obtained 11,179 contigs of potential prokaryotic origin and classified them according to the NCBI's prokaryotic attributes table. The majority of these sequences correspond to either Bacteroidetes (16 %) or Proteobacteria (78 %). The latter were dominated by gamma- (39 %, including sequences related to the pathogenic genus Francisella), and alpha-proteobacterial (30 %) sequences. Analysis of the Pfam domain family and Gene Ontology term variation revealed that the most frequent terms that appear unique to this consortium correspond to proteins involved in "transmembrane transporter activity" and "oxidoreductase activity". Furthermore, we identified genes that encode for enzymes involved in the catabolism of complex substance for energy reserves. We also characterized members of the transposase and integrase superfamilies, whose role in bacterial evolution is well documented, as well as putative antifreeze proteins. Antibiotic treatments of E. focardii cultures delayed the cell division of the ciliate. To conclude, our results indicate that this consortium is largely represented by bacteria derived from the original Antarctic sample and may contribute to the survival of E. focardii in laboratory condition. Furthermore, our results suggest that these bacteria may have a more general role in E. focardii survival in its natural cold and oxidative environment.
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Affiliation(s)
- Sandra Pucciarelli
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, 62032, Italy,
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16
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Thelaus J, Andersson A, Broman T, Bäckman S, Granberg M, Karlsson L, Kuoppa K, Larsson E, Lundmark E, Lundström JO, Mathisen P, Näslund J, Schäfer M, Wahab T, Forsman M. Francisella tularensis subspecies holarctica occurs in Swedish mosquitoes, persists through the developmental stages of laboratory-infected mosquitoes and is transmissible during blood feeding. MICROBIAL ECOLOGY 2014; 67:96-107. [PMID: 24057273 PMCID: PMC3907667 DOI: 10.1007/s00248-013-0285-1] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Accepted: 08/28/2013] [Indexed: 05/29/2023]
Abstract
In Sweden, mosquitoes are considered the major vectors of the bacterium Francisella tularensis subsp. holarctica, which causes tularaemia. The aim of this study was to investigate whether mosquitoes acquire the bacterium as aquatic larvae and transmit the disease as adults. Mosquitoes sampled in a Swedish area where tularaemia is endemic (Örebro) were positive for the presence of F. tularensis deoxyribonucleic acid throughout the summer. Presence of the clinically relevant F. tularensis subsp. holarctica was confirmed in 11 out of the 14 mosquito species sampled. Experiments performed using laboratory-reared Aedes aegypti confirmed that F. tularensis subsp. holarctica was transstadially maintained from orally infected larvae to adult mosquitoes and that 25% of the adults exposed as larvae were positive for the presence of F. tularensis-specific sequences for at least 2 weeks. In addition, we found that F. tularensis subsp. holarctica was transmitted to 58% of the adult mosquitoes feeding on diseased mice. In a small-scale in vivo transmission experiment with F. tularensis subsp. holarctica-positive adult mosquitoes and susceptible mice, none of the animals developed tularaemia. However, we confirmed that there was transmission of the bacterium to blood vials by mosquitoes that had been exposed to the bacterium in the larval stage. Taken together, these results provide evidence that mosquitoes play a role in disease transmission in part of Sweden where tularaemia recurs.
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Affiliation(s)
- J Thelaus
- Division of CBRN Defence and Security, Swedish Defence Research Agency, 90182, Umea, Sweden,
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17
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Abstract
Our understanding of the virulence and pathogenesis of Francisella spp. has significantly advanced in recent years, including a new understanding that this organism can form biofilms. What is known so far about Francisella spp. biofilms is summarized here and future research questions are suggested. The molecular basis of biofilm production has begun to be studied, especially the role of extracellular carbohydrates and capsule, quorum sensing and two-component signaling systems. Further work has explored the contribution of amoebae, pili, outer-membrane vesicles, chitinases, and small molecules such as c-di-GMP to Francisella spp. biofilm formation. A role for Francisella spp. biofilm in feeding mosquito larvae has been suggested. As no strong role in virulence has been found yet, Francisella spp. biofilm formation is most likely a key mechanism for environmental survival and persistence. The significance and importance of Francisella spp.’s biofilm phenotype as a critical aspect of its microbial physiology is being developed. Areas for further studies include the potential role of Francisella spp. biofilms in the infection of mammalian hosts and virulence regulation.
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Affiliation(s)
- Monique L van Hoek
- School of Systems Biology and National Center for Biodefense and Infectious Diseases; George Mason University; Manassas, VA USA
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18
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Theodorakopoulos N, Bachar D, Christen R, Alain K, Chapon V. Exploration of Deinococcus-Thermus molecular diversity by novel group-specific PCR primers. Microbiologyopen 2013; 2:862-72. [PMID: 23996915 PMCID: PMC3831646 DOI: 10.1002/mbo3.119] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Revised: 07/04/2013] [Accepted: 07/05/2013] [Indexed: 11/07/2022] Open
Abstract
The deeply branching Deinococcus-Thermus lineage is recognized as one of the most extremophilic phylum of bacteria. In previous studies, the presence of Deinococcus-related bacteria in the hot arid Tunisian desert of Tataouine was demonstrated through combined molecular and culture-based approaches. Similarly, Thermus-related bacteria have been detected in Tunisian geothermal springs. The present work was conducted to explore the molecular diversity within the Deinococcus-Thermus phylum in these extreme environments. A set of specific primers was designed in silico on the basis of 16S rRNA gene sequences, validated for the specific detection of reference strains, and used for the polymerase chain reaction (PCR) amplification of metagenomic DNA retrieved from the Tataouine desert sand and Tunisian hot spring water samples. These analyses have revealed the presence of previously undescribed Deinococcus-Thermus bacterial sequences within these extreme environments. The primers designed in this study thus represent a powerful tool for the rapid detection of Deinococcus-Thermus in environmental samples and could also be applicable to clarify the biogeography of the Deinococcus-Thermus phylum.
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Affiliation(s)
- Nicolas Theodorakopoulos
- CEA, DSV, IBEB, SBVME, LIPM, F-13108, Saint-Paul-lez-Durance, France; CNRS, UMR 7265, F-13108, Saint-Paul-lez-Durance, France; Université d'Aix-Marseille, F-13108, Saint-Paul-lez-Durance, France; IRSN, PRP-ENV, SERIS, L2BT, F-13115, Saint Paul-lez-Durance, France
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19
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Duncan D, Vogler A, Wolcott M, Li F, Sarovich D, Birdsell D, Watson L, Hall T, Sampath R, Housley R, Blyn L, Hofstadler S, Ecker D, Keim P, Wagner D, Eshoo M. Identification and typing of Francisella tularensis
with a highly automated genotyping assay. Lett Appl Microbiol 2012; 56:128-34. [DOI: 10.1111/lam.12022] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Revised: 10/24/2012] [Accepted: 10/29/2012] [Indexed: 01/21/2023]
Affiliation(s)
- D.D. Duncan
- Ibis Biosciences, an Abbott company; Carlsbad CA USA
| | - A.J. Vogler
- Center for Microbial Genetics and Genomics; Northern Arizona University; Flagstaff AZ USA
| | - M.J. Wolcott
- United States Army Medical Research Institute of Infectious Diseases; Fort Detrick MD USA
| | - F. Li
- Ibis Biosciences, an Abbott company; Carlsbad CA USA
| | - D.S. Sarovich
- Center for Microbial Genetics and Genomics; Northern Arizona University; Flagstaff AZ USA
| | - D.N. Birdsell
- Center for Microbial Genetics and Genomics; Northern Arizona University; Flagstaff AZ USA
| | - L.M. Watson
- Center for Microbial Genetics and Genomics; Northern Arizona University; Flagstaff AZ USA
| | - T.A. Hall
- Ibis Biosciences, an Abbott company; Carlsbad CA USA
| | - R. Sampath
- Ibis Biosciences, an Abbott company; Carlsbad CA USA
| | - R. Housley
- Ibis Biosciences, an Abbott company; Carlsbad CA USA
| | - L.B. Blyn
- Ibis Biosciences, an Abbott company; Carlsbad CA USA
| | | | - D.J. Ecker
- Ibis Biosciences, an Abbott company; Carlsbad CA USA
| | - P. Keim
- Center for Microbial Genetics and Genomics; Northern Arizona University; Flagstaff AZ USA
| | - D.M. Wagner
- Center for Microbial Genetics and Genomics; Northern Arizona University; Flagstaff AZ USA
| | - M.W. Eshoo
- Ibis Biosciences, an Abbott company; Carlsbad CA USA
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Duodu S, Larsson P, Sjödin A, Soto E, Forsman M, Colquhoun DJ. Real-time PCR assays targeting unique DNA sequences of fish-pathogenic Francisella noatunensis subspecies noatunensis and orientalis. DISEASES OF AQUATIC ORGANISMS 2012; 101:225-234. [PMID: 23324419 DOI: 10.3354/dao02514] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Specific identification and differentiation of the 2 subspecies of the fish pathogen Francisella noatunensis, namely, F. noatunensis subsp. noatunensis and F. noatunensis subsp. orientalis, remains a major diagnostic challenge. Following whole-genome sequencing and analysis of representatives of all major subclades of the genus Francisella, specific genomic regions were identified for each of the subspecies of this fish pathogen. Two specific real-time quantitative PCR assays, directed at hypothetical genes within these regions were developed. Specificity was confirmed by lack of signal and cross-reactivity with the closest relative, F. philomiragia, and other common bacterial fish pathogens. Both assays, used either as monoplex or multiplex, have a limit of detection of 10 genome equivalents. The quantitative sensitivity of the assays was not affected by the presence of kidney tissues or DNA from Atlantic cod Gadus morhua or tilapia Oreochromis sp.
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Affiliation(s)
- Samuel Duodu
- Section for Bacteriology, Norwegian Veterinary Institute, PO Box 750, Sentrum, 0106 Oslo, Norway.
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